Tire Co-Op in Hawaii

[StephenM]

I think we need this more urgently for the 21's, as the tires wear much faster and the wheels are also more prone to cracking/denting. I already had one replaced through my road hazard warranty due to cracking.

 

[Akikiki]

I think we need this more urgently for the 21's, as the tires wear much faster and the wheels are also more prone to cracking/denting. I already had one replaced through my road hazard warranty due to cracking.

Well, I don't think you are asking my agreement, but doing the same thing for 21's is a good idea too. I guess you already know that the overall outside diameter of a 19" wheel and tire and a 21" wheel and tire are the same. You could use a 19" wheel and tire as a spare, since you would use it only temporarily. And this would most likely be cheaper to get a 10" tire than a 21" tire, and the 21" wheel from TM new is more than $750 more than a 19" wheel.

 

[StephenM]

Well, I don't think you are asking my agreement, but doing the same thing for 21's is a good idea too. I guess you already know that the overall outside diameter of a 19" wheel and tire and a 21" wheel and tire are the same. You could use a 19" wheel and tire as a spare, since you would use it only temporarily. And this would most likely be cheaper to get a 10" tire than a 21" tire, and the 21" wheel from TM new is more than $750 more than a 19" wheel.

I actually did not know (or forgot) that the diameters are the same after a tire is mounted for both 19&21" wheels. Sounds like a good idea to have one around as an option over towing.

 

[Akikiki]

Yes, the outside diameter is the same. This is why no adjustment is required when switching between 19's and 21's.
Although the outside diameter of the two wheels are different, the one tire is a lower profile (distance between the inside diameter and outside diameter, this allows the outside of both tires to be the same.

 

[Akikiki]

Copied from TM Model S Forum. NoMorePetrol offered his research to everyone, so I wanted to make sure it was available to TMC users.

Spare tire solution
NoMorePetrol | December 3, 2015

A compact spare (wheel and tire) that fits in the frunk. Rolling diameter, lug pattern, load - all good. $340.
http://www.bimmerzone.com/BMW_Performance_Spare_Tire/BIM-SST-F25-KIT.html
A Tesla sized centering ring for the spare (also shown on the page with the spare). $10.
http://www.bimmerzone.com/BMW_Performance_Spacers/PRT-7465.html
A 1/2 inch drive 21mm thin wall socket. $12.
http://amazon.com/Wilmar-Performance-Tool-W32925-2-Inch/dp/B00H8A57PS/re...
A 1/2 inch drive by 25 inch breaker bar (those lug nuts are on tight) for the socket. $20.
http://amazon.com/gp/product/B00MWVAUT6?psc=1&redirect=true&ref_=oh_aui_...
For a jack - low clearance, heavy load, high quality (it is holding your Model S) - I went with a 2011 Acura MDX jack.

The tire fits nicely in the frunk, as if the frunk was sized just for that purpose. The jack and the rest fit nicely behind the spare in the compartment. There is still quite a bit of room left in the frunk, around and on top of the spare. Put the tire in upside down so you also have the room "inside" the tire.

 

[dsmith2189]

Copied from TM Model S Forum. NoMorePetrol offered his research to everyone, so I wanted to make sure it was available to TMC users.

Spare tire solution
NoMorePetrol | December 3, 2015

A compact spare (wheel and tire) that fits in the frunk. Rolling diameter, lug pattern, load - all good. $340.
http://www.bimmerzone.com/BMW_Performance_Spare_Tire/BIM-SST-F25-KIT.html
A Tesla sized centering ring for the spare (also shown on the page with the spare). $10.
http://www.bimmerzone.com/BMW_Performance_Spacers/PRT-7465.html
A 1/2 inch drive 21mm thin wall socket. $12.
http://amazon.com/Wilmar-Performance-Tool-W32925-2-Inch/dp/B00H8A57PS/re...
A 1/2 inch drive by 25 inch breaker bar (those lug nuts are on tight) for the socket. $20.
http://amazon.com/gp/product/B00MWVAUT6?psc=1&redirect=true&ref_=oh_aui_...
For a jack - low clearance, heavy load, high quality (it is holding your Model S) - I went with a 2011 Acura MDX jack.

The tire fits nicely in the frunk, as if the frunk was sized just for that purpose. The jack and the rest fit nicely behind the spare in the compartment. There is still quite a bit of room left in the frunk, around and on top of the spare. Put the tire in upside down so you also have the room "inside" the tire.

Sounds like a plan, but I would add a torque wench to get those wheels torqued to the correct spec. (to get those lug nuts back on tight) * Note: not for removal of lug nuts, that could damage the torque wrench.
Like a TEKTON 24335 1/2-Inch Drive Click Torque Wrench, 10-150-Foot/Pound
the only other thing I might add is that many of these items might already be on island at Ron's performance or checker auto parts.

Then again... I found this spare... why put an ugly donut spare on when you can have this one... (similar diameter and -1" in width) for just a bit more. ($364.95)
This kit includes one Genuine BMW space saver aluminum wheel with 135/80/18 Pirelli tire. Spare tire is approximately 27 in dia x 5 in wide. Does not include jack or lug wrench.
go to http://www.bavauto.com/ and search for part# B36000195 or Emergency Spare Wheel and Tire (for X3)

 

[Akikiki]

dsmith, very good idea. You've already said it so clearly, no need for me to repeat it. Thanks.